Complications of spinal manipulation: A comprehensive review of the literature

Background. Spinal manipulative therapy (SMT) is a frequently applied therapy for back and neck pain. Serious complications of SMT are presented primarily in case reports. Many patients seen by physicians also seek care from therapists applying manipulative techniques. Therefore, background information on the risks of SMT is essential for physicians. Methods. Relevant case reports, surveys, and review articles were identified using a comprehensive search of online and bibliographical databases. For every case, a record was made of first author, publication year, country, age and sex of the patient, background of the manipulator, preexisting conditions, type of complication, and course of the complication. Based on case reports and surveys, an estimation was made of the risk for the most frequently reported complications: vertebrobasilar accidents (VBAs) and cauda equina syndrome (CES). Results. We derived 295 complications of spinal manipulations from the literature: 165 VBAs; 61 cases with disc herniation or progression to CES; 13 cerebral complications other than VBAs; and 56 other types of complications. The average age of patients with VBA was 38 years. Vertebrosbasilar accidents occur mainly after a cervical manipulation with a rotary component. Estimates of VBA range from 1 per 20,000 patients to 1 per 1 million cervical manipulations. The incidence of CES is estimated to be less than 1 per 1 million treatments. Conclusions. It is difficult to estimate the incidence of SMT complications, as they are probably under reported in the literature. Most non-VBA complications can be prevented by excluding patients with contraindications for SMT. Patients who develop complications such as CES should be treated as soon as possible. VBAs, however, are difficult to prevent and treat. Referral for SMT should not be made to practitioners applying rotary cervical manipulation. Information about the risk of VBA should be included in an informed consent procedure for cervical manipulation with thrust techniques.